Furnace for reducing ores.



G. GRDNDAL.

FURNACE FOR REDUCING DEBS. APPLIOATIOH FILED NOV. 24, 1902.

Patented Oct. 5, 1909.

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ANDREW. a 011mm cm PHOYDLXTHUGRAPHUS. wAswxm UNl'TElE STATES ET GUSTilF GR-iiNDAL, OF DZTUBSHOLM, SWEDEN, ASSIGNOR TO AMERICAN GRQNDAL, KJELLIN COMPANY, OF NEW YGBK, N. Y., A CORPORATIGN.

FURNACE FOR REDUCENG GEES.

Specification of Letters Patent.

Patented 5, 1909.

Application filed. November 24, 1908. Serial No. 445%,326.

double furnace is represented as an example, said furnace being particularly adapted for reducing pulverized iron ore formed into porous blocks or briquets.

Figure 1 is a longitudinal section on line 1-1 of Fig. Fig. 2 is a transverse section on line of Fig. 3 and Fig. 3 is a plan view partly in section.

a a are two parallel tunnel furnaces having vestibules Y) b and c 0 respectively at their ends. At the entrance ends the tunnel furnaces con'n'nunicate by a conduit (Z for the gas.

0 c are two regenerators.

f f are conduits from the regenerators to the middle of the tunnel furnaces or thereabout and g g are conduits leading to a shifting valve it. From the valve h a conduit 2' leads to a gas-generator, not shown, and a conduit j leads to the chimney is.

Z Z are conduits controlled by valves m m for leading air under pressure to the regenerators and n a are air openings in the conduits f f.

0 0. are trucks on which the ore hriquets are conveyed through the furnaces in any convenient manner, not shown; the briquets, however, may be carried through the tunnel furnaces on any other n'iovahle supporting device.

The double furnace and regenerators may be heated in the following way: Generator gas is introduced through the shifting valve /i and led through one of the regenerators for instance 0 into the tunnel furnace a and through the conduit (Z into the other tunnel furnace a and thence through the conduit f into the regenerator 0, air being allowed to enter through the air opening or openings n. The now is ignited heating the regenerator 6 and the combustion gases are discharged into the chimney it through the shifting valve 71. After the regenerator c has been heated sufficiently the air valve 027/ is closed, the valve 72. is shifted and the gas is led the opposite way through the tunnel furnaces. The gas is ignited at n, by the air pressed in through the valve m.

After the double furnace has been heated sutheiently trucks or other movable supporting device on which hriquets are piled are pushed through the vestibules 7) and Z) into the tunnel furnaces and by means of any suitable device the trucks are carried gradu ally through the tunnel furnaces in any con venieut manner. The operation is conducted in such a manner that the reduction of the ore completed when the trucks have passed the gas inlet from the conduits f or respectively. in the parts of the tunnel furnaces lying on the other side of said inlets the hriquets are allowed to cool in the same atmosphere, 2'. in the portion of the gas mixture filling said parts of the furnaces. The gas is led into the furnace under pressure and the doors of the tunnel furnaces and vestibules should be tight so as to prevent the atmospheric air from entering the furnace, and thereby an oxidation of the reduced ore is prevented. These parts of the tunnel furnaces in which the cooling is effected, should have such a length that the material loaded on the trucks occupying the vestibules c c for the time being has cooled down sutliciently to be removed from the tunnel furnace without any danger of reonidizing about the time the trucks standing at the gas inlets from f f, 2'. c. the trucks whose material has been reduced, are to pass said inlets.

Vfhen the temperature of the regenerator through which the gas is fed has fallen so far that the does not leave the regencra tor at the desired temperature the direction of flow of the is reversed and the reducing operation is carried on continually.

1. A regenerative double furnace for re (lueing ore by means of gas, consisting of two tunnel furnaces located parallel to each other, means for conveying the. ore through said furnaces, a gas-conduit between the entrance ends of the furnaces, gas-supply, two regenerators, gas-conduits from each of said regencrators to each of the tunnel furnaces, a supply of combustion air und r pressure, conduits for said air opening into said g ms-conduits, controlling valves in said airconduits, and means for shifting the flow of gas to the regenerators and to a chimney, substantially as and for the purpose set forth.

2. A regenerative furnace for reducing ore by means of gas consisting of a plurality of tunnel furnaces, means for conveying ore through said furnaces, a gas conduit uniting the entrance ends of said tunnel furnaces, a gas supply, a plurality of regenerators, gas conduits leading therefrom to said tunnel furnaces, a combustion air supply under pressure, conduits for said air opening into said gas conduits, means to control said air supply, and means for shifting the flow of gas to the regenerators and to a chimney, substantially as and for the purpose described.

In testimony whereof I have signed my name to this specification, in the presence of,

two subscribing Witnesses.

GUSTAF GRONDAL. Witnesses Funnnrn L. EN UIST, NILs ENQUIST; 

